In a related-art counterweight device for a general elevator, a plurality of weights are laminated and mounted inside a frame body. The frame body is formed by assembling a pair of stiles, a crosshead, and a plank into a rectangular shape. The crosshead and the plank are fixed to the stiles by welding or a plurality of bolts. Further, a pair of counterweight guide rails for guiding raising and lowering of the counterweight device is installed inside a hoistway. On both sides of the frame body in a width direction thereof, a plurality of guide shoes to be brought into engagement with the counterweight guide rails are mounted (see, for example, Patent Literature 1).
When the counterweight guide rails are deformed (deflected) due to seismic shaking, the related-art counterweight device described above cannot follow the deformation to cause the guide shoes to derail from the guide rails in some cases. This is because the frame body does not deform in response to the deformation of the guide rails and the guide shoes are of fixed type. Further, the laminated weights are merely masses of iron. Therefore, the weights do not have a function of reducing the seismic shaking.
On the other hand, a cage is formed by combining a plurality of thin plates. Therefore, a certain amount of energy of the seismic shaking can be absorbed. In addition, a car platform is supported through an intermediation of a vibration isolation rubber. Further, a passenger can also absorb a certain amount of the seismic shaking. Thus, a car scarcely derails from car guide rails due to the seismic shaking.
For the derailment of the counterweight device described above, a method of using a frame body having a double-frame structure including an outer frame and an inner frame and providing a plurality of vibration isolation rubbers between the outer frame and the inner frame has been proposed (see, for example, Patent Literature 2).
Further, in another related-art elevator apparatus, the counterweight is bent in an upper portion and a lower portion of the hoistway and is extended in an intermediate portion of the hoistway (see, for example, Patent Literature 3).